fix for bug#16642 (Events: No INFORMATION_SCHEMA.EVENTS table)

post-review change - use pointer instead of copy on the stack.
WL#1034 (Internal CRON)
 This patch adds INFORMATION_SCHEMA.EVENTS table with the following format:
  EVENT_CATALOG  - MYSQL_TYPE_STRING  (Always NULL)
  EVENT_SCHEMA   - MYSQL_TYPE_STRING  (the database)
  EVENT_NAME     - MYSQL_TYPE_STRING  (the name)
  DEFINER        - MYSQL_TYPE_STRING  (user@host)
  EVENT_BODY     - MYSQL_TYPE_STRING  (the body from mysql.event)
  EVENT_TYPE     - MYSQL_TYPE_STRING  ("ONE TIME" | "RECURRING")
  EXECUTE_AT     - MYSQL_TYPE_TIMESTAMP (set for "ONE TIME" otherwise NULL)
  INTERVAL_VALUE - MYSQL_TYPE_LONG    (set for RECURRING otherwise NULL)
  INTERVAL_FIELD - MYSQL_TYPE_STRING  (set for RECURRING otherwise NULL)
  SQL_MODE       - MYSQL_TYPE_STRING  (for now NULL)
  STARTS         - MYSQL_TYPE_TIMESTAMP (starts from mysql.event)
  ENDS           - MYSQL_TYPE_TIMESTAMP (ends from mysql.event)
  STATUS         - MYSQL_TYPE_STRING  (ENABLED | DISABLED)
  ON_COMPLETION  - MYSQL_TYPE_STRING  (NOT PRESERVE | PRESERVE)
  CREATED        - MYSQL_TYPE_TIMESTAMP
  LAST_ALTERED   - MYSQL_TYPE_TIMESTAMP
  LAST_EXECUTED  - MYSQL_TYPE_TIMESTAMP
  EVENT_COMMENT  - MYSQL_TYPE_STRING

  SQL_MODE is NULL for now, because the value is still not stored in mysql.event .
Support will be added as a fix for another bug.

 This patch also adds SHOW [FULL] EVENTS [FROM db] [LIKE pattern]
1. SHOW EVENTS shows always only the events on the same user,
   because the PK of mysql.event is (definer, db, name) several 
   users may have event with the same name -> no information disclosure.
2. SHOW FULL EVENTS - shows the events (in the current db as SHOW EVENTS)
   of all users. The user has to have PROCESS privilege, if not then
   SHOW FULL EVENTS behave like SHOW EVENTS.
3. If [FROM db] is specified then this db is considered.
4. Event names can be filtered with LIKE pattern.
  SHOW EVENTS returns table with the following columns, which are subset of
  the data which is returned by SELECT * FROM I_S.EVENTS
   Db
   Name
   Definer 
   Type
   Execute at
   Interval value
   Interval field 
   Starts 
   Ends
   Status

1 files changed, 41 insertions, 22 deletions

diff --git a/sql/event.cc b/sql/event.cc
index 6d62be903bd..5decbefe287 100644
--- a/sql/event.cc
+++ b/sql/event.cc
@@ -77,7 +77,7 @@ evex_queue_init(EVEX_QUEUE_TYPE *queue)
 }
 
 
-static
+
 int sortcmp_lex_string(LEX_STRING s, LEX_STRING t, CHARSET_INFO *cs)
 {
  return cs->coll->strnncollsp(cs, (unsigned char *) s.str,s.length,
@@ -176,7 +176,9 @@ evex_open_event_table(THD *thd, enum thr_lock_type lock_type, TABLE **table)
 
 int
 evex_db_find_event_aux(THD *thd, const LEX_STRING dbname,
-                       const LEX_STRING ev_name, TABLE *table)
+                       const LEX_STRING ev_name,
+                       const LEX_STRING user_name,
+                       TABLE *table)
 {
   byte key[MAX_KEY_LENGTH];
   DBUG_ENTER("evex_db_find_event_aux");
@@ -190,11 +192,17 @@ evex_db_find_event_aux(THD *thd, const LEX_STRING dbname,
     same fields.
   */
   if (dbname.length > table->field[EVEX_FIELD_DB]->field_length ||
-      ev_name.length > table->field[EVEX_FIELD_NAME]->field_length)
+      ev_name.length > table->field[EVEX_FIELD_NAME]->field_length ||
+      user_name.length > table->field[EVEX_FIELD_DEFINER]->field_length)
+      
     DBUG_RETURN(EVEX_KEY_NOT_FOUND);
 
-  table->field[0]->store(dbname.str, dbname.length, &my_charset_bin);
-  table->field[1]->store(ev_name.str, ev_name.length, &my_charset_bin);
+  table->field[EVEX_FIELD_DB]->store(dbname.str, dbname.length, &my_charset_bin);
+  table->field[EVEX_FIELD_NAME]->store(ev_name.str, ev_name.length,
+                                       &my_charset_bin);
+  table->field[EVEX_FIELD_DEFINER]->store(user_name.str, user_name.length,
+                                          &my_charset_bin);
+
   key_copy(key, table->record[0], table->key_info, table->key_info->key_length);
 
   if (table->file->index_read_idx(table->record[0], 0, key,
@@ -283,10 +291,15 @@ evex_fill_row(THD *thd, TABLE *table, event_timed *et, my_bool is_update)
       from 1. Thus +1 offset is needed!
     */
     table->field[EVEX_FIELD_TRANSIENT_INTERVAL]->store((longlong)et->interval+1);
+
+    table->field[EVEX_FIELD_EXECUTE_AT]->set_null();
   }
   else if (et->execute_at.year)
   {
     // fix_fields already called in init_execute_at
+    table->field[EVEX_FIELD_INTERVAL_EXPR]->set_null();
+    table->field[EVEX_FIELD_TRANSIENT_INTERVAL]->set_null();
+
     table->field[EVEX_FIELD_EXECUTE_AT]->set_notnull();
     table->field[EVEX_FIELD_EXECUTE_AT]->store_time(&et->execute_at,
                                                     MYSQL_TIMESTAMP_DATETIME);    
@@ -351,9 +364,9 @@ db_create_event(THD *thd, event_timed *et, my_bool create_if_not,
     my_error(ER_EVENT_OPEN_TABLE_FAILED, MYF(0));
     goto err;
   }
-
+  
   DBUG_PRINT("info", ("check existance of an event with the same name"));
-  if (!evex_db_find_event_aux(thd, et->dbname, et->name, table))
+  if (!evex_db_find_event_aux(thd, et->dbname, et->name, et->definer, table))
   {
     push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_NOTE,
 		      ER_EVENT_ALREADY_EXISTS, ER(ER_EVENT_ALREADY_EXISTS),
@@ -398,10 +411,9 @@ db_create_event(THD *thd, event_timed *et, my_bool create_if_not,
     goto err;
   }
 
-  strxmov(definer, et->definer_user.str, "@", et->definer_host.str, NullS);
-  if ((ret=table->field[EVEX_FIELD_DEFINER]->
-       store(definer, et->definer_user.length + 1 + et->definer_host.length,
-             system_charset_info)))
+  if ((ret=table->field[EVEX_FIELD_DEFINER]->store(et->definer.str,
+                                                   et->definer.length,
+                                                   system_charset_info)))
   {
     my_error(ER_EVENT_STORE_FAILED, MYF(0), et->name.str, ret);
     goto err;
@@ -464,7 +476,9 @@ db_update_event(THD *thd, event_timed *et, sp_name *new_name)
   TABLE *table;
   int ret= EVEX_OPEN_TABLE_FAILED;
   DBUG_ENTER("db_update_event");
+  DBUG_PRINT("enter", ("dbname: %.*s", et->dbname.length, et->dbname.str));
   DBUG_PRINT("enter", ("name: %.*s", et->name.length, et->name.str));
+  DBUG_PRINT("enter", ("user: %.*s", et->name.length, et->name.str));
   if (new_name)
     DBUG_PRINT("enter", ("rename to: %.*s", new_name->m_name.length,
                                             new_name->m_name.str));
@@ -485,7 +499,8 @@ db_update_event(THD *thd, event_timed *et, sp_name *new_name)
       goto err;    
     }
   
-    if (!evex_db_find_event_aux(thd, new_name->m_db, new_name->m_name, table))
+    if (!evex_db_find_event_aux(thd, new_name->m_db, new_name->m_name,
+                                et->definer, table))
     {
       my_error(ER_EVENT_ALREADY_EXISTS, MYF(0), new_name->m_name.str);
       goto err;
@@ -498,7 +513,7 @@ db_update_event(THD *thd, event_timed *et, sp_name *new_name)
     row (copied into record[1] later
   */
   if (EVEX_KEY_NOT_FOUND == evex_db_find_event_aux(thd, et->dbname, et->name,
-                                                     table))
+                                                   et->definer, table))
   {
     my_error(ER_EVENT_DOES_NOT_EXIST, MYF(0), et->name.str);
     goto err;    
@@ -547,6 +562,7 @@ err:
      db_find_event()
        thd      THD
        name     the name of the event to find
+       definer  who owns the event
        ett      event's data if event is found
        tbl      TABLE object to use when not NULL
    
@@ -556,11 +572,11 @@ err:
 */
 
 static int
-db_find_event(THD *thd, sp_name *name, event_timed **ett, TABLE *tbl)
+db_find_event(THD *thd, sp_name *name, LEX_STRING definer, event_timed **ett,
+              TABLE *tbl)
 {
   TABLE *table;
   int ret;
-  const char *definer;
   char *ptr;
   event_timed *et;  
   DBUG_ENTER("db_find_event");
@@ -575,7 +591,8 @@ db_find_event(THD *thd, sp_name *name, event_timed **ett, TABLE *tbl)
     goto done;
   }
 
-  if ((ret= evex_db_find_event_aux(thd, name->m_db, name->m_name, table)))
+  if ((ret= evex_db_find_event_aux(thd, name->m_db, name->m_name, definer,
+                                   table)))
   {
     my_error(ER_EVENT_DOES_NOT_EXIST, MYF(0), name->m_name.str);
     goto done;    
@@ -616,6 +633,7 @@ done:
      evex_load_and_compile_event()
        thd       THD
        spn       the name of the event to alter
+       definer   who is the owner
        use_lock  whether to obtain a lock on LOCK_event_arrays or not
        
    RETURN VALUE
@@ -625,7 +643,8 @@ done:
 */
 
 static int
-evex_load_and_compile_event(THD * thd, sp_name *spn, bool use_lock)
+evex_load_and_compile_event(THD * thd, sp_name *spn, LEX_STRING definer,
+                            bool use_lock)
 {
   int ret= 0;
   MEM_ROOT *tmp_mem_root;
@@ -640,7 +659,7 @@ evex_load_and_compile_event(THD * thd, sp_name *spn, bool use_lock)
 
   thd->reset_n_backup_open_tables_state(&backup);
   // no need to use my_error() here because db_find_event() has done it
-  if ((ret= db_find_event(thd, spn, &ett, NULL)))
+  if ((ret= db_find_event(thd, spn, definer, &ett, NULL)))
     goto done;
 
   thd->restore_backup_open_tables_state(&backup);
@@ -756,7 +775,7 @@ evex_create_event(THD *thd, event_timed *et, uint create_options,
   if (evex_is_running && et->status == MYSQL_EVENT_ENABLED)
   {
     sp_name spn(et->dbname, et->name);
-    ret= evex_load_and_compile_event(thd, &spn, true);
+    ret= evex_load_and_compile_event(thd, &spn, et->definer, true);
   }
   VOID(pthread_mutex_unlock(&LOCK_evex_running));
 
@@ -809,11 +828,11 @@ evex_update_event(THD *thd, event_timed *et, sp_name *new_name,
   if (et->status == MYSQL_EVENT_ENABLED)
   {
     if (new_name)
-      ret= evex_load_and_compile_event(thd, new_name, false);
+      ret= evex_load_and_compile_event(thd, new_name, et->definer, false);
     else
     {
       sp_name spn(et->dbname, et->name);
-      ret= evex_load_and_compile_event(thd, &spn, false);
+      ret= evex_load_and_compile_event(thd, &spn, et->definer, false);
     }
     if (ret == EVEX_COMPILE_ERROR)
       my_error(ER_EVENT_COMPILE_ERROR, MYF(0));
@@ -851,7 +870,7 @@ evex_drop_event(THD *thd, event_timed *et, bool drop_if_exists,
     goto done;
   }
 
-  if (!(ret= evex_db_find_event_aux(thd, et->dbname, et->name, table)))
+  if (!(ret= evex_db_find_event_aux(thd, et->dbname,et->name,et->definer,table)))
   {
     if ((ret= table->file->ha_delete_row(table->record[0])))
     {